Systems and methods for controlling directionality of ions in an edge region by using an electrode within a coupling ring

ABSTRACT

Systems and methods for controlling directionality of ion flux at an edge region within a plasma chamber are described. One of the systems includes a radio frequency (RF) generator that is configured to generate an RF signal, an impedance matching circuit coupled to the RF generator for receiving the RF signal to generate a modified RF signal, and a plasma chamber. The plasma chamber includes an edge ring and a coupling ring located below the edge ring and coupled to the first impedance matching circuit to receive the modified RF signal. The coupling ring includes an electrode that generates a capacitance between the electrode and the edge ring to control the directionality of the ion flux upon receiving the modified RF signal.

FIELD

The present embodiments relate to systems and methods for controllingdirectionality of ions in an edge region of a plasma chamber by using anelectrode within a coupling ring.

BACKGROUND

Plasma systems are used to control plasma processes. A plasma systemincludes multiple radio frequency (RF) sources, an impedance match, anda plasma reactor. A workpiece is placed inside the plasma chamber andplasma is generated within the plasma chamber to process the workpiece.

It is important that the workpiece be processed in a similar or uniformmanner. To process the workpiece in a similar or uniform manner, variousparameters associated with the plasma reactor are controlled. As anexample, it is important to control directionality of ion flux duringprocessing of the workpiece. The control in directionality helpsincrease an etch rate and achieve a certain aspect ratio of features ofthe workpiece.

With the processing of the workpiece in the uniform manner, it isimportant to simultaneously maintain lifetime of various components ofthe plasma chamber. With an application of RF power to some of thecomponents, the components wear faster and do not last for theirlifetime. Moreover, due to such wear, the components adversely affectthe directionality of ion flux, which adversely affects the uniformityin processing of the workpiece.

It is in this context that embodiments described in the presentdisclosure arise.

SUMMARY

Embodiments of the disclosure provide apparatus, methods and computerprograms for controlling directionality of ions in an edge region of aplasma chamber by using an electrode within a coupling ring. It shouldbe appreciated that the present embodiments can be implemented innumerous ways, e.g., a process, an apparatus, a system, a piece ofhardware, or a method on a computer-readable medium. Several embodimentsare described below.

It is difficult to meet process specifications at the edge of a waferdue to a tradeoff between a profile angle or tilt at which the wafer isetched and an etch rate. The etch rate depends upon ion flux at the edgeof the wafer and chemistry, e.g., mixture, types, etc., of one or moreprocess gases used to process the wafer. The ion flux at the edgereaching the wafer is a function of ion flux that enters the plasmasheath and the shape of the plasma sheath at the edge. The ion focusingeffect is a function of a difference in wafer plasma sheath thicknessabove the wafer and edge ring plasma sheath thickness above the edgering that controls the plasma sheath beyond the edge of the wafer. It isimportant to maintain a uniform plasma density beyond the edge of thewafer and minimize the difference between the wafer plasma sheath andthe edge ring plasma sheath to improve the etch rate and to maintain aprofile angle to be about 90 degrees, e.g., between 89.5 degrees and90.5 degrees, between 89 degrees and 91 degrees, etc. Also, it isdesirable to control wear of the edge ring so that the edge ring is usedfor its lifetime, e.g., greater than 500 hours, etc.

In some embodiments, a knob for independent control of plasma parametersassociated with the edge ring is provided. The knob is provided byembedding a powered electrode in a coupling ring, and providing radiofrequency (RF) power to the electrode or by coupling the electrode via avariable impedance RF filter to ground. The providing of the RF power issometimes referred to as providing active power to the electrode and thecoupling of the electrode via the variable impedance to ground issometimes referred to as providing passive power to the electrode. Thereis no optimization in upper electrode step location, edge ring heightand shape, edge ring coupling materials, etc., to control the plasmaparameters. However, in some embodiments, the upper electrode steplocation, the edge ring height and shape, and/or the edge ring materialsare controlled in addition to the active or passive power provided tothe electrode to control the plasma parameters.

In various embodiments, a capacitively coupled RF powered edge ring isdescribed for improving performance at the edge of the wafer. By varyingan amount of the active or passive power coupled to the edge ring,plasma density of the plasma at the edge region, sheath uniformity ofthe plasma at the edge region, etch rate uniformity of the plasma at theedge region, and tilt at which the wafer is etched in the edge regionare controlled. There is no provision of RF or direct current (DC) powerdirectly to the edge ring. The capacitive coupling of power to the edgering reduces, e.g., eliminates, etc., chances of any arcing between thematerials of the edge ring and RF feed parts used to deliver powerdirectly to the edge ring.

In some embodiments, a system for controlling directionality of ion fluxat the edge region within a plasma chamber is described. The systemincludes an RF generator that is configured to generate an RF signal, animpedance matching circuit coupled to the RF generator for receiving theRF signal to generate a modified RF signal, and the plasma chamber. Theplasma chamber includes the edge ring and the coupling ring locatedbelow the edge ring and coupled to the impedance matching circuit toreceive the modified RF signal. The coupling ring includes the electrodethat generates a capacitance between the electrode and the edge ring tocontrol the directionality of the ion flux upon receiving the modifiedRF signal.

In various embodiments, a system for controlling directionality of ionflux at the edge region within a plasma chamber is described. The systemincludes a first RF filter that is configured to output a first filteredRF signal, a second RF filter coupled to the first RF filter forreceiving the first filtered RF signal to output a second filtered RFsignal, and a plasma chamber. The plasma chamber includes the edge ringand the coupling ring located below the edge ring and coupled to thesecond RF filter. The coupling ring includes the electrode configured toreceive the second filtered RF signal to further generate a capacitancebetween the electrode and the edge ring to control the directionality ofthe ion flux upon receiving the second filtered RF signal.

In some embodiments, a system for controlling directionality of ion fluxat the edge region within a plasma chamber is described. The systemincludes an RF filter that is configured to output a filtered RF signaland a plasma chamber. The plasma chamber includes the edge ring, and thecoupling ring located below the edge ring and coupled to the RF filterto receive the filtered RF signal. The coupling ring includes theelectrode that generates a capacitance between the electrode and theedge ring to control the directionality of the ion flux upon receivingthe filtered RF signal.

Some advantages of the herein described systems and embodiments includeachieving the approximately 90 degree profile angle. An amount of theactive or passive power supplied to the electrode within the couplingring that is coupled to the edge ring is changed to achieve the 90degree profile angle. Ion flux is measured and the ion flux iscontrolled based on the measurement. The ion flux is controlled bycontrolling an active power source or a passive power source that iscoupled to the electrode within the coupling ring to change acapacitance between the electrode and the edge ring. The capacitance ischanged to achieve the approximately 90 degree profile angle. Thecapacitance is used to control a voltage of the edge ring to furthercontrol the etch rate of etching the wafer at the edge region. Thevoltage of the edge ring is proportional to an impedance of the edgering compared to ground. The profile angle helps achieve an edgeprofile, e.g., a top CD, a bow CD, etc., uniformity that is less than apre-determined amount, e.g., less than 3%, less than 2%, less than 4%,etc.

Moreover, other advantages of the herein described systems and methodsinclude extension of the edge ring lifetime by varying edge ringvoltage. Once the edge ring is worn, e.g., has reduced height, etc., theplasma sheath is bent and ion flux becomes focused on the wafer edge. Asa result, edge tilt becomes out of a range defined in a specification.Adjusting the edge ring voltage leads to more uniform plasma sheath andputs wafer edge process parameters back into the range defined in thespecification. By implementing the electrode within the coupling ringinstead of the edge ring, lifetime of the edge ring is increased.

Other aspects will become apparent from the following detaileddescription, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments are understood by reference to the following descriptiontaken in conjunction with the accompanying drawings.

FIG. 1 a diagram of an embodiment of a plasma system to illustratecontrolling directionality of ions in an edge region of a plasma chamberby using a coupling ring.

FIG. 2A is a diagram of an embodiment of a system to illustrate couplingof an electrode within the coupling ring to an impedance matchingcircuit (IMC) via a radio frequency (RF) filter and providing activepower to the electrode.

FIG. 2B is a diagram of an embodiment of a system to illustrateproviding passive power to the electrode embedded within the couplingring.

FIG. 3A is a diagram of an embodiment of a system to illustrate use ofion flux to tune power supplied by an x megahertz (MHz) RF generator oran x1 kilohertz (kHz) RF generator to control impedance of plasma withinthe edge region to further control directionality of an ion flux in theedge region.

FIG. 3B is a diagram of an embodiment of a system to illustrate use ofion flux to tune an RF filter to control the impedance within the edgeregion to further control directionality of the ion flux within the edgeregion.

FIG. 3C is a diagram of an embodiment of a system to illustrate use ofdirect current (DC) bias to tune power supplied by the x MHz RFgenerator or the x1 kHz RF generator to control the impedance of theplasma within the edge region to further control directionality of theion flux in the edge region.

FIG. 3D is a diagram of an embodiment of a system to illustrate use ofthe DC bias to tune the RF filter to control the impedance of the plasmawithin the edge region to further control directionality of the ion fluxin the edge region.

FIG. 4A is a diagram of an embodiment of a mesh electrode, which is anexample of the electrode embedded within the coupling ring.

FIG. 4B is a diagram of an embodiment of a ring shaped electrode, whichis another example of the electrode.

FIG. 5 is a diagram of an embodiment of a plasma chamber to illustrate aportion of a feed ring and a connection between the portion and a powerpin.

FIG. 6 is a diagram of an embodiment of a portion of the plasma chamberto illustrate a location of the electrode with respect to the remainingcomponents of the plasma chamber.

FIG. 7 is a diagram of an embodiment of a system for illustrating thefeed ring that is coupled to an RF rod.

FIG. 8A is an embodiment of a graph to illustrate a change in anormalized etch rate of a wafer that is processed within the plasmachamber with a change in an amount of power that is supplied to theelectrode.

FIG. 8B is a diagram of a portion of the plasma chamber to illustrate achange in directionality of ion flux with a change in an amount of powerthat is supplied to the electrode.

FIG. 9A is an embodiment of a graph to illustrate a change in an etchrate of etching a substrate with a change in a capacitance of an RFfilter.

FIG. 9B is an embodiment of a graph that plots a peak voltage of theedge ring versus a capacitance of the passive RF filter of FIG. 9A.

DETAILED DESCRIPTION

The following embodiments describe systems and methods for controllingdirectionality of ions in an edge region of a plasma chamber by using anelectrode within a coupling ring. It will be apparent that the presentembodiments may be practiced without some or all of these specificdetails. In other instances, well known process operations have not beendescribed in detail in order not to unnecessarily obscure the presentembodiments.

FIG. 1 is a diagram of an embodiment of a plasma system 100 toillustrate controlling directionality of ions in an edge region 102 of aplasma chamber 104 by using a coupling ring 112. The plasma system 100includes an x megahertz (MHz) radio frequency (RF) generator, a z MHz RFgenerator, an x1 kilohertz (kHz) RF generator, an impedance matchingcircuit (IMC) 108, another IMC 113, and the plasma chamber 104. Theplasma chamber 104 includes an edge ring 110, the coupling ring 112, anda chuck 114, e.g., an electrostatic chuck (ESC), etc. The edge ring 110performs many functions, including positioning the substrate 120 on thechuck 114 and shielding the underlying components, of the plasma chamber104, not protected by substrate 120 from being damaged by the ions ofthe plasma formed within the plasma chamber 104. The chuck 114, e.g., alower electrode, etc., is made of a metal, e.g., anodized aluminum,alloy of aluminum, etc.

The coupling ring 112 is located below the edge ring 110 and is coupledto the edge ring 110. The coupling ring 112 is made from an electricalinsulator material, e.g., a dielectric material, ceramic, glass,composite polymer, aluminum oxide, etc. The edge ring 110 confinesplasma to an area above a substrate 120 and/or protects the chuck 114from erosion by the plasma. The edge ring 110 is made from one or morematerials, e.g., crystal silicon, polycrystalline silicon, siliconcarbide, quartz, aluminum oxide, aluminum nitride, silicon nitride, etc.Both the edge ring 110 and the coupling ring 112 are located besides thechuck 114. An edge of the substrate 120 is placed over the edge ring 110and the edge of the edge ring 110 is located in the edge region 102. Asan example, the edge region 102 extends from the edge ring 110 by apre-determined distance of 10 millimeters to 15 millimeters along aradius of the chuck 114 from an edge of the chuck 114. The plasmachamber 104 has a chamber wall 115, which is coupled to ground.

The x MHz RF generator is coupled via an RF cable 126, the IMC 108 andan RF transmission line 122 to the coupling ring 112. Moreover, the x1kHz RF generator and the z MHz RF generators are coupled via the IMC 113and another RF transmission line 124 to the chuck 114. An RFtransmission line includes an RF rod and an insulator sleeve thatsurrounds the RF rod. The x1 kHz RF generator is coupled to the IMC 113via an RF cable 128 and the z MHz RF generator is coupled to the IMC 113via an RF cable 130. Examples of the x1 kHz RF generator include agenerator having a frequency of operation of 400 kHz, a generator havinga frequency of operation ranging between 360 kHz and 440 kHz, etc.Examples of the x MHz RF generator include a generator having afrequency of operation of 2 MHz, a generator having a frequency ofoperation of 27 MHz etc. Example of the z MHz RF generator include agenerator having a frequency of operation of 27 MHz, a generator havinga frequency of operation of 60 MHz, etc.

The x1 kHz generates an RF signal and sends the RF signal to the IMC113. Similarly, the z MHz RF generator generates an RF signal and sendsthe RF signal to the IMC 113. The IMC 113 matches an impedance of aload, e.g., the RF transmission line 124, the plasma chamber 104, etc.,coupled to an output of the IMC 113 with that of a source, e.g., the RFcable 128, the RF cable 130, the x1 kHz RF generator and the z MHz RFgenerator, etc., coupled to inputs of the IMC 113 to provide a modifiedRF signal at its output. Similarly, the IMC 108 matches an impedance ofa load, e.g., the plasma chamber 104, the RF transmission line 112,etc., that is coupled an output of the IMC 108 with that of a source,e.g., the x MHz RF generator, the RF cable 126, etc., that is coupled aninput of the IMC 108 to provide a modified RF signal at its output.

The modified RF signal at the output of the IMC 113 is sent to the chuck114 to modify an impedance of plasma, e.g., to generate and maintainplasma, etc., within the plasma chamber 104 at a center region 132 ofthe plasma chamber 104. The center region 132 is located adjacent to theedge region 102 and is surrounded by the edge region 102. The centerregion extends from one end of the edge region 102 via a center of thechuck 114 to an opposite end of the edge region 102. Moreover, themodified RF signal at the output of the IMC 108 is sent to the couplingring 112 to modify an impedance of plasma and a directionality of ionswithin the edge region 102 of the plasma chamber 104. The plasma isgenerated or maintained when one or more process gases, e.g., oxygencontaining gas, fluorine containing gas, etc., are supplied via an upperelectrode 121 to the center region 132 of the plasma chamber 104.

The upper electrode 121 faces the chuck 114 and a gap is formed betweenthe upper electrode 121 and the chuck 114. The upper electrode 121 islocated within the plasma chamber 104 and is made of a conductivematerial. The plasma within the plasma chamber 104 is used to processthe substrate 120. For example, the plasma is used to etch the substrate120, to deposit materials on the substrate 120, to clean the substrate120, etc.

In some embodiments, the plasma chamber 104 includes additional parts,e.g., an upper electrode extension that surrounds the upper electrode121, a dielectric ring between the upper electrode 121 and the upperelectrode extension, confinement rings located besides edges of theupper electrode 121 and the edge ring 110 to surround the gap within theplasma chamber 104, etc.

In various embodiments, the RF signal that is generated by the x MHz RFgenerator is synchronized with the RF signal that is generated by the x1kHz RF generator and with the RF signal that is generated by the z MHzRF generator. For example, at a time the RF signal generated by the xMHz RF generator is pulsed from a low state to a high state, the RFsignal that is generated by the x1 kHz RF generator is pulsed from thelow state to the high state, and the RF signal that is generated by thez MHz RF generator is pulsed from the low state to the high state. Asanother example, at a time the RF signal generated by the x MHz RFgenerator is pulsed from the high state to the low state, the RF signalthat is generated by the x1 kHz RF generator is pulsed from the highstate to the low state, and the RF signal that is generated by the z MHzRF generator is pulsed from the high state to the low state. The highstate for an RF signal has a higher level, e.g., root mean square value,peak-to-peak amplitude, etc., of power of the RF signal compared to thelow state for the RF signal.

In some embodiments, the RF signal that is generated by the x MHz RFgenerator is not synchronized with the RF signal that is generated bythe x1 kHz RF generator, or is not synchronized with the RF signal thatis generated by the z MHz RF generator, or is not synchronized with theRF signal that is generated by the x1 kHz RF generator and is notsynchronized with the RF signal that is generated by the z MHz RFgenerator.

FIG. 2A is a diagram of an embodiment of a system 200 to illustratecoupling of an electrode 202 within the coupling ring 112 to the IMC 108via an RF filter 208 and providing active power to the electrode 202.The RF filter 208 reduces an amount of RF current from reaching the x1kHz RF generator or the x MHz RF generator that is coupled to the RFfilter 208 via the IMC 108 to prevent any damage by RF power of the RFcurrent to the x1 kHz RF generator or the x MHz RF generator and anycomponent of an RF delivery system between IMC 108 and the electrode202. As an example, the RF filter 208 includes one or more capacitors,or one or more inductors, or a combination of the capacitors andinductors. The RF current is generated by the plasma within the plasmachamber 206.

The system 200 includes a plasma chamber 206, which is an example of theplasma chamber 104 (FIG. 1). The system 200 further includes the x MHzRF generator or the x1 kHz RF generator, the IMC 108, and the RF filter208. The x MHz RF generator or the x1 kHz RF generator is coupled viathe RF cable 126 to the IMC 108, which is coupled via the RFtransmission line 122 to the RF filter 208. The RF filter 208 is coupledvia a power pin 204 to the electrode 202. The electrode 202 is embeddedwithin the coupling ring 112. For example, no portion of the electrode202 is exposed outside the coupling ring 112. As another example, theelectrode 202 is embedded within the coupling ring 112 to be closer toan upper surface 212 of the coupling ring 112 compared to a lowersurface 214 of the coupling ring 112. The upper surface 212 is adjacentto the edge ring 110 and the lower surface 214 is adjacent to aninsulator ring 216 of the plasma chamber 206. The insulator ring 216 islocated below the coupling ring 112 and is made of an electricalinsulating material, e.g., quartz, etc.

The power pin 204 includes a coax cable 220 and a sleeve 222. The sleeve222 covers the coax cable 220 to insulate the coax cable 220 fromelectrical fields surrounding the coax cable 220. The sleeve 222 is madeof an electrical insulator material, e.g., plastic, glass, a combinationof plastic and glass, etc. The power pin 204 is coupled to the electrode202 and is coupled via a feed ring to an RF transmission line, which iscoupled to the RF filter 208. As an example, the feed ring is made of aconductive metal, e.g., aluminum, copper, etc. A portion of the powerpin 204 is located besides the insulator ring 216, a facilities plate224, and the remaining portion of the power pin 204 is surrounded by thecoupling ring 112. The facilities plate 224 is made from a metal, e.g.,aluminum, etc.

The facilities plate 224 is located below the chuck 114 and is coupledto the RF transmission line 124. Multiple ground rings 226, which aremade of a metal, e.g., aluminum, etc., surround a portion of aninsulator ring 228 and the insulator ring 216, and are connected toground. The insulator ring 228 is made from an insulating material,e.g., quartz, etc., and protects the edge ring 110 from being coupledwith direct current (DC) power.

The plasma chamber 206 further includes the upper electrode 121 thatfaces the chuck 114. A gap 232 is formed between the upper electrode 121and the chuck 114. Plasma is formed within the gap 232 for processingthe substrate 120. Multiple confinement rings 238 are stacked tosurround the gap 232 and a portion of the upper electrode 121. Theconfinement rings 238 are opened or closed via a motor mechanism tocontrol pressure within the gap 232 and/or to control an amount ofplasma flowing out from the gap 232 to one or more vacuum pumps locatedbelow the plasma chamber 206. A cover ring 241, e.g., a quartz coverring, etc., is overlaid on top of the ground rings 226 to protect theground rings 226 from RF power of the plasma.

The x MHz RF generator or the x1 kHz RF generator supplies an RF signalto the IMC 108. The IMC 108 matches an impedance of a load, e.g., the RFtransmission line 122, the RF filter 208, and the plasma chamber 206with that of a source, e.g., the RF cable 126 and the x MHz RF generatoror the x1 kHz RF generator, etc., to generate a modified RF signal. Themodified RF signal passes via RF transmission line 122, the RF filter208, the feed ring and the power pin 204 to the electrode 202. Thereception of the modified RF signal by the electrode 202 changesimpedance of the plasma within the edge region 102, a portion of whichis located within the gap 232. The change in impedance is used to changea directionality of ion flux within the edge region 102 to controlplasma processing, e.g., etching, deposition, cleaning, etc., of thesubstrate 120 within the edge region 102.

In one embodiment, the system 200 excludes the RF filter 208 and IMC 108is coupled via the RF transmission line 122 to the feed ring.

FIG. 2B is a diagram of an embodiment of a system 250 to illustrateproviding passive power control to the electrode 202 embedded within thecoupling ring 112. The system 250 is the same as the system 200 exceptthat the system 250 includes an RF filter 207 that is coupled to the RFfilter 208 via an RF cable 254 at its output and is coupled to ground.The RF filter 207 includes one or more capacitors, or one or moreinductors, or a combination of the capacitors and inductors. Forexample, the RF filter 207 includes a capacitor in parallel with aninductor. As another example, the RF filter 207 includes a capacitor. Asyet another example, the RF filter 207 includes a capacitor in serieswith an inductor. In one embodiment, one or more capacitors of the RFfilter 207 are variable and one or more inductors of the RF filter 207are variable.

The RF filter 207 provides an impedance path to ground to an RF signalthat is received from the plasma within the edge region 102. An RFsignal is generated from the plasma within the edge region 102 and flowsvia the edge ring 110 and the capacitance between the electrode 202 andthe edge ring 110 to the electrode 202, which outputs an RF signal. TheRF signal from the electrode 202 passes through the power pin 204 andthe feed ring to the RF filter 208. The RF filter 208 filters out any DCpower within the RF signal to output a filtered RF signal. The filteredRF signal passes via the RF cable 254 and the RF filter 207 to ground. Acapacitance, or an inductance, or a combination of the capacitance andinductance of the RF filter 207 determines an amount of the filtered RFsignal that flows to ground to modify the impedance of the plasma withinthe edge region 102 to further control the directionality of the ionflux in the edge region 102.

In various embodiments, the RF filter 207 filters a portion of the RFsignal that is received from the plasma within the edge region 102 tooutput a filtered signal via the RF transmission line 254 to the RFfilter 208. The portion of the RF signal flows to the ground that iscoupled to the RF filter 207. The filtered signal received by the RFfilter 208 via the RF transmission line 254 is filtered by the RF filter208 to remove DC power to output a filtered signal to the coax cable 220of the power pin 204. The filtered signal is provided via the coax cable220 to the electrode 202 to change a capacitance between the electrode202 and the edge ring 110. The capacitance is changed to change animpedance of plasma within the edge region 102.

In some embodiments, the RF filter 208 is excluded and the RF filter 207is coupled to the power pin 204 via the RF transmission line 254.

FIG. 3A is a diagram of an embodiment of a system 300 to illustratetuning of power supplied by the x MHz RF generator or the x1 kHz RFgenerator to control the impedance of the plasma within the edge region102 to further control directionality of the ion flux in the edge region102. The system 300 is the same as the system 200 of FIG. 2A except thatthe system 300 further includes a planar ion flux probe 302, ameasurement sensor 304 and a host computer system 306. An example of theplanar ion flux probe is a Langmuir probe. Examples of the host computersystem 306 include a computer, a tablet, a smart phone, etc. Examples ofthe measurement sensor 304 include a complex voltage sensor or a complexcurrent sensor.

The planar ion flux probe 302 is inserted via an opening in the upperelectrode 121 and has a spacer between a conductive portion, e.g.,silicon, etc., of the ion flux probe 302 and the upper electrode 121.The planar ion flux probe 302 has a portion, e.g., a cylindricalportion, a polygonal portion, etc., that has a surface that is exposedto the plasma associated with the edge region 102. The planar ion fluxprobe 302 is coupled via an RF cable 308 to the measurement sensor 304,which is coupled via a transfer cable 310, e.g., a serial transfercable, a parallel transfer cable, a Universal Serial Bus (USB) cable,etc., to the host computer system 306. The host computer system 306 iscoupled via a transfer cable 312, e.g., a serial transfer cable, aparallel transfer cable, a USB cable, etc., to the x MHz RF generator orthe x1 kHz RF generator. A serial transfer cable is used to transferdata serially, e.g., one bit at a time, etc. A parallel transfer cableis used to transfer data in a parallel manner, e.g., multiple bits at atime, etc.

The planar ion flux probe 302 measures ion flux, e.g., an amount of ionflow per unit surface area of the ion flux probe 302, an amount ofcurrent per unit surface area of the ion flux probe 302, etc., of theplasma associated with the edge region 102 to generate an RF signal. TheRF signal passes via the RF cable 308 to the measurement sensor 304,which measures a complex voltage or a complex current of the RF signal.The measurement sensor 304 outputs the measured complex voltage or themeasured complex current as data via the transfer cable 310 to the hostcomputer system 306. The host computer 306 includes a processor and amemory device. Examples of the processor include a central processingunit (CPU), a controller, an application specific integrated circuit(ASIC), or a programmable logic device (PLD), etc. Examples of thememory device include a read-only memory (ROM), a random access memory(RAM), a hard disk, a volatile memory, a non-volatile memory, aredundant array of storage disks, a Flash memory, etc.

The processor of the host computer system 306 determines an amount ofpower to be supplied by the x MHz RF generator or the x1 kHz RFgenerator that is coupled to the IMC 108 based on the measured complexvoltage or the measured complex current. For example, a correspondence,e.g., a one-to-one relationship, an association, a mapping, etc.,between a pre-determined complex voltage or a pre-determined complexcurrent and the power that is supplied by the x MHz RF generator or thex1 kHz RF generator is stored in the memory device that is coupled tothe processor. The pre-determined complex voltage or the pre-determinedcomplex current corresponds to, e.g., has a one-to-one relationshipwith, is mapped to, etc., a pre-determined amount of ion flux to begenerated within the edge region 102, and the relationship is stored inthe memory device of the host computer system 306. The processordetermines from the measured complex current that the measured complexcurrent does not match or is not within a pre-determined range from thepre-determined complex current to be achieved. The processor determinesbased on the correspondence between the pre-determined complex currentand an amount of power to be supplied by the x MHz RF generator or thex1 kHz RF generator the amount of power. The processor generates acontrol signal indicating to the x MHz RF generator or the x1 kHz RFgenerator that the amount of power is to be supplied by the x MHz RFgenerator or the x1 kHz RF generator.

In one embodiment, the processor determines from the measured complexvoltage that the measured complex voltage does not match or is notwithin a pre-determined range from the pre-determined complex voltage tobe achieved. The processor determines based on the correspondencebetween the pre-determined complex voltage and the amount of power to besupplied by the x MHz RF generator or the x1 kHz RF generator the amountof power. The processor generates a control signal indicating to the xMHz RF generator or the x1 kHz RF generator that the amount of power isto be supplied by the x MHz RF generator or the x1 kHz RF generator.

Upon receiving the amount of power, the x MHz RF generator or the x1 kHzRF generator generates and supplies and RF signal having the amount ofpower via the RF cable 126 to the IMC 108. The IMC 208 matches animpedance of the load coupled to the IMC 208 with that of the sourcecoupled to the IMC 108 to generate a modified RF signal from the RFsignal received from the x MHz RF generator or the x1 kHz RF generator.The modified RF signal is provided to the electrode 202 via the RFfilter 208, the feed ring coupled to the RF filter 208, and the coaxcable 220. The capacitance between the electrode 202 and a lower surfaceof the edge ring 110 changes when the electrode 202 receives themodified RF signal to change an impedance of the plasma within the edgeregion 102 to further modify a direction of the ion flux within the edgeregion 102.

FIG. 3B is a diagram of an embodiment of a system 320 to illustratetuning of the RF filter 207 to control the impedance within the edgeregion 102 to further control directionality of the ion flux within theedge region 102. The system 320 is the same as the system 250 (FIG. 2B)except that the system 320 includes the planar ion flux probe 302, themeasurement sensor 304, the host computer system 306, a power supply328, and a motor 322, e.g., a DC motor, an alternating current (AC)motor, etc. Examples of the power supply 328 include an AC power supplyor a DC power supply. The power supply 328 is coupled to the hostcomputer system 306 via a transfer cable 324. Moreover, the motor 322 iscoupled to the power supply 328 via a cable 330 and is coupled to the RFfilter 207 via a connection mechanism 326. Examples of the connectionmechanism 326 include one or more rods, one or more gears, or acombination thereof. The connection mechanism 326 is connected to acircuit component, e.g., an inductor, a capacitor, etc., of the RFfilter 207 to change a parameter, e.g., capacitance, inductance, etc.,of the circuit component. For example, the connection mechanism 326rotates to change an area between two parallel plates of a capacitor ofthe RF filter 207 and/or a distance between the plates. As anotherexample, the connection mechanism 326 to displace a core surrounded by acoil of an inductor of the RF filter 207 to change an inductance of theinductor.

The processor determines from the complex current, measured by themeasurement sensor 304, that the measured complex current does not matchor is not within the pre-determined range from the pre-determinedcomplex current to be achieved. The processor determines based on thecorrespondence among the pre-determined complex current, an amount ofpower, e.g., DC power, AC power, etc., to be supplied by the powersupply 328 and a pre-determined capacitance of the RF filter 207 to beachieved, the amount of power. The processor generates a control signalindicating to the power supply 328 that the amount of power is to besupplied by the power supply 328 to achieve the pre-determinedcapacitance of the RF filter 207.

In one embodiment, the processor determines from the measured complexvoltage that the measured complex voltage does not match or is notwithin the pre-determined range from the pre-determined complex voltageto be achieved. The processor determines based on the correspondenceamong the pre-determined complex voltage, the pre-determined capacitanceof the RF filter 207 to be achieved, and the amount of power to besupplied by the power supply 328, the amount of power. The processorgenerates a control signal indicating to the power supply 328 that theamount of power is to be supplied by the power supply 328.

The control signal is sent via the transfer cable 324 to the powersupply 328. Upon receiving the amount of power, the power supply 328generates and supplies the amount of power via the cable 330 to themotor 322. A stator of the motor 322 receives the amount of power togenerate an electric field, which rotates a rotor of the motor 322. Therotation of the rotor rotates the connection mechanism 326 to change theparameter of the RF filter 207 to achieve the pre-determinedcapacitance. The change in the parameter, e.g., the capacitance, etc.,changes an amount of RF power that flows via the RF filter 207 to theground coupled to the RF filter 207 to further change the capacitancebetween the electrode 202 and the edge ring 110. The capacitance betweenthe electrode 202 and the edge ring 110 is changed via the RF cable 254,the RF filter 208, the feed ring coupled to the RF filter 208, and thecoax cable 220. The change in the capacitance changes an amount of powerof the filtered signal flowing from the RF filter 207 to the RF filter208 via the RF transmission line 254. The change in the amount of powerchanges an impedance of the plasma within the edge region 102 to furthermodify the directionality of the ion flux within the edge region 102.

FIG. 3C is a diagram of an embodiment of a system 350 to illustrate useof DC bias to tune power supplied by the x MHz RF generator or the x1kHz RF generator to control the impedance of the plasma within the edgeregion 102 to further control directionality of the ion flux in the edgeregion 102. The system 350 is the same as the system 300 (FIG. 3A)except that the system 350 includes a measurement sensor 354, and a DCbias probe 352 instead of the planar ion flux probe 302 (FIG. 3A) andthe measurement sensor 304 (FIG. 3A). An example of the measurementsensor 354 is a DC bias voltage sensor.

A portion of the DC bias sensor 352 is extended into the edge ring 110via an opening in the edge ring 110 and the remaining portion of the DCbias sensor 352 is extended into the insulator ring 228 via an openingin the insulator ring 228. The DC bias sensor 352 is connected to themeasurement sensor 354 via a cable 356 to the measurement sensor 354.The measurement sensor 354 provides a measurement of a DC bias, e.g., aDC bias voltage, etc., that is generated by RF power of the edge ring110. The RF power of the edge ring 110 is based on RF power of theplasma within the edge region 102. The measurement sensor 354 isconnected to the host computer system 306 via the transfer cable 310.

The DC bias probe 352 senses a DC bias voltage of the edge ring 110 togenerate an electrical signal and the DC bias voltage is induced by RFpower of the plasma in the edge region 102. The electrical signal issent via the cable 356 to the measurement sensor 354, which measures theDC bias voltage based on the electrical signal. An amount of themeasured DC bias voltage is sent as data from the measurement sensor 354via the transfer cable 310 to the host computer system 306.

The processor of the host computer system 306 determines an amount ofpower to be supplied by the x MHz RF generator or the x1 kHz RFgenerator that is coupled to the IMC 108 based on the measured DC biasvoltage. For example, a correspondence, e.g., a one-to-one relationship,an association, a mapping, etc., between a DC bias voltage and an amountof power that is supplied by the x MHz RF generator or the x1 kHz RFgenerator in the memory device that is coupled to the processor. Theprocessor of the host computer system 306 determines from the measuredDC bias voltage that the measured DC bias voltage does not match or isnot within a pre-determined range from a pre-determined DC bias voltageto be achieved. The processor determines based on the correspondencebetween the pre-determined DC bias voltage and an amount of power to besupplied by the x MHz RF generator or the x1 kHz RF generator the amountof power. The processor generates a control signal indicating to the xMHz RF generator or the x1 kHz RF generator that the amount of power isto be supplied by the x MHz RF generator or the x1 kHz RF generator.

Upon receiving the amount of power, the x MHz RF generator or the x1 kHzRF generator generates and supplies an RF signal having the amount ofpower via the RF cable 126 to the IMC 108. The IMC 108 matches animpedance of the load coupled to the IMC 208 with that of the sourcecoupled to the IMC 108 to generate a modified RF signal from the RFsignal received from the x MHz RF generator or the x1 kHz RF generator.The modified RF signal is provided to the electrode 202 via the RFfilter 208, the feed ring coupled to the RF filter 208, and the coaxcable 220. The capacitance between the electrode 202 and the edge region110 changes when the electrode 202 receives the modified RF signal tochange an impedance of the plasma within the edge region 102 to furthermodify a direction of the ion flux within the edge region 102.

FIG. 3D is a diagram of an embodiment of a system 370 to illustrate useof DC bias voltage to tune the RF filter 207 to control the impedance ofthe plasma within the edge region 102 to further control directionalityof the ion flux in the edge region 102. The system 370 is the same asthe system 320 (FIG. 3B) except that the system 370 includes themeasurement sensor 354, and the DC bias probe 352 instead of the planarion flux probe 302 (FIG. 3B) and the measurement sensor 304 (FIG. 3B).As explained above with reference to FIG. 3C, the measurement sensor 354outputs the measured DC bias voltage to the host computer system 306 viathe transfer cable 310.

The processor of the host computer system 306 determines an amount ofpower to be supplied by the power supply 328 based on the measured DCbias voltage. For example, a correspondence, e.g., a one-to-onerelationship, an association, a mapping, etc., between a DC bias voltageand an amount of power that is supplied by the power supply 328 isstored in the memory device that is coupled to the processor. Theprocessor of the host computer system 306 determines from the measuredDC bias voltage that the measured DC bias voltage does not match or isnot within a pre-determined range from a pre-determined DC bias voltageto be achieved. The processor determines based on the correspondencebetween the pre-determined DC bias voltage and the amount of power to besupplied by the power supply 328 the amount of power. The processorgenerates a control signal indicating to the power supply 328 that theamount of power is to be supplied by the power supply 328.

The control signal is sent via the transfer cable 324 to the powersupply 328. Upon receiving the amount of power, as described above withreference to FIG. 3B, the power supply 328 generates and supplies theamount of power via the cable 330 to the motor 322, which rotates tochange the parameter of the RF filter 207, and the change in theparameter changes the capacitance between the electrode 202 and the edgering 110. The capacitance between the electrode 202 and the edge ring110 is changed to change the impedance of the plasma within the edgeregion 102 to further change the directionality of the ion flux withinthe edge region 102.

In some embodiments, a current, e.g., a complex current, etc., or avoltage, e.g., a DC bias voltage, a complex voltage, etc., is referredto herein as a variable.

FIG. 4A is a diagram of an embodiment of a mesh electrode 402, which isembedded within the coupling ring 112 (FIG. 1). The mesh electrode 402includes multiple crossings of wires to form a net-like structure and isan example of the electrode 202 (FIG. 2A). The mesh electrode 402 ismade of a metal, e.g., aluminum, copper, etc.

FIG. 4B is a diagram of an embodiment of a ring shaped electrode 404,which is an example of the electrode 202 (FIG. 2A). The ring shapedelectrode 404 is tubular in structure or flat, e.g., plate-shaped, etc.,in structure. The ring shaped electrode 404 is made of a metal, e.g.,aluminum, copper, etc.

FIG. 5 is a diagram of an embodiment of a plasma chamber 500 toillustrate a portion of a feed ring 502 and a connection between theportion and the power pin 204. The plasma chamber 500 is an example ofthe plasma chamber 104 (FIG. 1). The feed ring 502 is connected at oneend 506 to an RF rod 504 of the RF transmission line 122 (FIG. 1) and atan opposite end 508 to the coax cable 220 of the power pin 204. Theplasma chamber 500 includes an RF rod 510 of the RF transmission line124 (FIG. 1). The RF rod 510 is situated within an RF cylinder 512,which is surrounded at its bottom portion by another RF cylinder 514.

The modified RF signal that is sent via the RF transmission line 122from the IMC 108 is sent via the RF rod 504 of the RF transmission line122 and the end 506 to the feed ring 502. A portion of the modified RFsignal transfers from the end 506 via the end 508 and the coax cable 220to the electrode 202 embedded within the coupling ring 112 for providingcapacitive coupling between the electrode 202 and the edge ring 110.

In some embodiments in which the passive power is provided to theelectrode 202, the RF rod 504 is of the RF transmission line 254 insteadof the RF transmission line 122 (FIG. 1). The RF transmission line 254couples the RF filter 207 to the RF filter 208 (FIG. 2B).

In various embodiments, the RF filter 208 is coupled to the RF rod 504of the RF transmission line 254 and is coupled to the feed ring 502. Forexample, in an embodiment in which passive RF power is flowing from theground that is connected to the RF filter 207 towards the electrode 202,an input of the RF filter 208 is coupled to the RF rod 504 and an outputof the RF filter 208 is coupled to the feed ring 502. As anotherexample, in an embodiment in which passive RF power from the edge region102 is flowing to the ground that is coupled to the RF filter 207, aninput of the RF filter 208 is coupled to the feed ring 502 and an outputof the RF filter 208 is coupled to the RF rod 504. As yet anotherexample, the RF filter 208 is coupled to the end 506 of the arm 716 andis coupled to the RF rod 504.

In an embodiment in which the active power is used, an input of the RFfilter 208 is coupled to the RF rod 504 that is further coupled to theIMC 108 (FIG. 2A) and an output of the RF filter 208 is coupled to thefeed ring 502.

FIG. 6 is a diagram of an embodiment of a portion 650 of a plasmachamber, which is an example of the plasma chamber 104 (FIG. 1), toillustrate a location of the electrode 202 with respect to the remainingcomponents of the plasma chamber. The portion 650 include an insulatorring 652 of the plasma chamber. The insulator ring 652 surrounds aportion of an insulator ring 604 and a portion of the insulator ring 652is located below the insulator ring 604. The insulator ring 604 islocated below another insulator ring 654.

The insulator ring 654 is adjacent to the coupling ring 112 and is belowan insulator ring 612 that surrounds the edge ring 110. The couplingring 112 is adjacent to the chuck 114. The edge ring 110 is overlaid ontop of a portion 608 of the coupling ring 112. The portion 608 of thecoupling ring 112 acts like a dielectric between the electrode 202 and alower surface of the edge ring 110 so that capacitive coupling isestablished between the electrode 202 and the edge ring 110. The portion608 creates a dielectric between the edge ring 110 and a remainingportion 606 of the coupling ring 112. The insulator ring 612 issurrounded by a movable ground ring 614, which is coupled to ground. Themovable ground ring 614 is located on top of a fixed ground ring 616,which is also coupled to ground.

The insulator 654 is located adjacent to the chuck 114, the facilitiesplate 224, and the coupling ring 112 on its inner side and to the fixedground ring 616 at its outer side. Moreover, the insulator ring 604 islocated below the facilities plate 224, which supports the chuck 114.The fixed ground ring 616 is adjacent to and surrounds the insulatorring 654 and on top of the insulator ring 652.

The confinement rings 238 (FIGS. 2A & 2B) include a confinement ringportion 656 and a confinement ring horizontal portion 658, e.g., aslotted ring, etc. The upper electrode 121 is surrounded by an upperelectrode extension 660.

The gap 232 formed between the upper electrode 121 and the chuck 114 issurrounded by the upper electrode 121, the upper electrode extension660, the confinement ring portion 656, the confinement ring horizontalportion 658, the insulator ring 612, the edge ring 110, and the chuck114.

The coupling ring 112 is surrounded by the edge ring 110, the insulatorring 654, and the chuck 114. For example, the coupling ring 112 isadjacent to the chuck 114, the edge ring 110, and the insulator ring654. As another example, the edge ring 110 is located on top of thecoupling ring 112 in which the electrode 202 is embedded, the chuck 114is located adjacent to an inner side of the coupling ring 112, and theinsulator ring 654 is located adjacent to an outer side of the couplingring 112. The coax cable 220 passes via the insulator ring 604 and theinsulator ring 654 to be connected to the electrode 202 located withinthe portion 606 of the coupling ring 112.

FIG. 7 is a diagram of an embodiment of a system 700 for illustratingthe feed ring 502 that is coupled to the RF rod 504. The feed ring 502includes a circular portion 708 that is connected to multiple arms 710,712, 714, and 716. The circular portion 708 is flat or is ring-shaped.The arm 716 is connected at the end 506 to the RF rod 504 and at anopposite end 718 to the circular portion 708. For example, the arm 716is fitted to the RF rod 504 at the end 506 via a fitting mechanism,e.g., a screw, a bolt, a clamp, a nut, or a combination thereof, etc.Similarly, the arm 710 is connected at an end 720 to a power pin 702.For example, the arm 710 is fitted to the power pin 702 at the end 720via the fitting mechanism. The power pin 702 is the same in structureand function as that of the power pin 204. For example, the power pin702 includes a coax cable and a sleeve that surrounds at least a portionof the coax cable. The arm 710 is connected at an opposite end 722 tothe circular portion 708.

Moreover, the arm 712 is connected at an end 724 to a power pin 704,which is the same in structure and function as that of the power pin204. For example, the power pin 704 includes a coax cable and a sleevethat surrounds at least a portion of the coax cable. As an example, thearm 712 is fitted to the power pin 704 at the end 724 via the fittingmechanism. The arm 712 is connected at an opposite end 726 to thecircular portion 708.

Furthermore, the arm 714 is connected at the end 508 to the power pin204. The arm 714 is connected at an opposite end 728 to the circularportion 708. The arm 710 extends from the circular portion 708 toconnect to the coax cable of the power pin 702, the arm 712 extends fromthe circular portion 708 to connect to the coax cable of the power pin704, and the arm 714 extends from the circular portion 798 to connect tothe coax cable 220 of the power pin 204. The power pin 702, e.g. thecoax cable of the power pin 702, etc., is connected at a point 730 tothe electrode 202 embedded within the coupling ring 112. Moreover, thepower pin 704, e.g. the coax cable of the power pin 704, etc., isconnected at a point 732 to the electrode 202, and the power pin 204,e.g., the coax cable 220, etc., is connected at a point 734 to theelectrode 202.

The modified RF signal that is received via the RF rod 504 and theimpedance matching circuit 108 (FIG. 1) is sent via the arm 716 to thecircular portion 708, and is divided between the arms 710, 712, and 714.A portion of power of the modified RF signal passes via the arm 710 andthe power pin 702, e.g. the coax cable of the power pin 702, etc., tothe electrode 202, another portion of the power of the modified RFsignal passes via the arm 712 and the power pin 704, e.g. the coax cableof the power pin 704, etc., to the electrode 202, and yet anotherportion of the power passes via the arm 714 and the power pin 204, e.g.,the coax cable 220, etc., to the electrode 202.

In some embodiments, the feed ring 502 includes any other number ofarms, e.g., two, one, four, five, etc., that extend from the circularportion 708 to connect to the electrode 202 within the coupling ring112.

In various embodiments, instead of the circular portion 708, a portionof another shape, e.g., oval, polygonal, etc., is used.

FIG. 8A is an embodiment of a graph 800 to illustrate a change in anormalized etch rate of a wafer that is processed within the plasmachamber 104 with a change is an amount of power that is supplied to theelectrode 202 (FIG. 2A). The wafer is an example of the substrate 120(FIG. 1). The graph 800 plots the normalized etch rate versus a radiusof the wafer when the chuck 114 of the plasma chamber 104 (FIG. 1) issupplied with RF power from the x1 kHz and z MHz RF generators via theIMC 113 (FIG. 1), and the electrode 202 is supplied with RF power fromthe x MHz RF generator via the IMC 108 (FIG. 1).

The graph 800 includes three plots 802, 804, and 806. The plot 802 isgenerated when an amount of RF power P1 of the x MHz RF generator issupplied via the IMC 108 to the electrode 202. The plot 804 is generatedwhen an amount of RF power P2 of the x MHz RF generator is supplied viathe IMC 108 to the electrode 202 and the plot 806 is generated when anamount of RF power P3 of the x MHz RF generator is supplied via the IMC108 to the electrode 202. The power P3 is greater than the power P2,which is greater than the power P1.

FIG. 8B is a diagram of a portion of the plasma chamber 104 (FIG. 1) toillustrate a change in directionality of ion flux with a change in theamount of power that is supplied to the electrode 202. When the amountof power P1 is supplied to the electrode 202, a directionality 812 a ofion flux 810 is such that the ions are not vertically directed towardsthe substrate 120 but are directed at a negative angle −θ, with respectto a 90 degree ion incidence angle, which is perpendicular to a diameterof the coupling ring 112. The angle θ is measured with respect to avertical axis perpendicular to the diameter of the coupling ring 112.This increases an etch rate of etching the substrate 120 in the edgeregion 102.

Moreover, when the amount of power P2 is supplied to the electrode 202,a directionality 812 b of the ion flux 810 is such that the ions arevertically directed, e.g. θ=0. The power P2 increases voltage of theedge ring 110 compared to the power P1. This decreases an etch rate ofetching the substrate 120 in the edge region 102 compared to when theamount of power P1 is supplied. The etch rate is decreased to achieve auniform etch rate at the edge region 102 and to achieve a flat plasmasheath at the edge region 102. For example, there is little or nodifference between levels of a plasma sheath over the wafer and over theedge ring 110.

Also, when the amount of power P3 is supplied to the electrode 202, adirectionality 812 c of the ion flux 810 is such that the ions are notvertically directed towards the substrate 120 but are directed at apositive angle θ. This decreases an etch rate of etching the substrate120 in the edge region 102 compared to when the amount of power P2 issupplied. By controlling an amount of power supplied to the electrode202, a directionality of the ion flux 810 is controlled via the powerpin 204 (FIG. 2A) and the electrode 202.

In some embodiments, instead of increasing the power that is supplied bythe electrode 202, an amount of capacitance of the RF filter 207 (FIG.2B) is increased to change the angle θ from a negative value to zerofurther to a positive value to control directionality of the ion flux810.

FIG. 9A is an embodiment of a graph 900 to illustrate a change in anetch rate of etching the substrate 120 (FIG. 1) with a change in acapacitance of the RF filter 207 (FIG. 2B). The graph 900 plots thenormalized etch rate versus the radius of the wafer for various valuesof capacitances of the RF filter 207. As a capacitance of the RF filter207 increases, an etch rate of the wafer at the edge region 102 (FIG. 1)decreases to achieve more uniformity in the etch rate.

FIG. 9B is an embodiment of a graph 902 that plots a peak voltage of theedge ring 110 (FIG. 1) versus the capacitance of the RF filter 207 (FIG.2B). As the capacitance of the RF filter 207 increases, the peak voltageof the edge ring 110 increases to change the directionality of the ionflux 810 (FIG. 8B) from negative θ to zero to positive θ.

It should be noted that in some of the above-described embodiments, anRF signal is supplied to the chuck 114 and the upper electrode 121 isgrounded. In various embodiments, an RF signal is applied to the upperelectrode 121 and the chuck 114 is grounded.

In some embodiments, each of the electrode 202 and the coupling ring 112are segmented into a plurality of segments. Each of the segments of theelectrode 202 is independently provided RF power from one or more RFgenerators.

Embodiments, described herein, may be practiced with various computersystem configurations including hand-held hardware units, microprocessorsystems, microprocessor-based or programmable consumer electronics,minicomputers, mainframe computers and the like. The embodiments,described herein, can also be practiced in distributed computingenvironments where tasks are performed by remote processing hardwareunits that are linked through a computer network.

In some embodiments, a controller is part of a system, which may be partof the above-described examples. The system includes semiconductorprocessing equipment, including a processing tool or tools, chamber orchambers, a platform or platforms for processing, and/or specificprocessing components (a wafer pedestal, a gas flow system, etc.). Thesystem is integrated with electronics for controlling its operationbefore, during, and after processing of a semiconductor wafer orsubstrate. The electronics is referred to as the “controller,” which maycontrol various components or subparts of the system. The controller,depending on processing requirements and/or a type of the system, isprogrammed to control any process disclosed herein, including a deliveryof process gases, temperature settings (e.g., heating and/or cooling),pressure settings, vacuum settings, power settings, RF generatorsettings, RF matching circuit settings, frequency settings, flow ratesettings, fluid delivery settings, positional and operation settings,wafer transfers into and out of a tool and other transfer tools and/orload locks connected to or interfaced with the system.

Broadly speaking, in a variety of embodiments, the controller is definedas electronics having various integrated circuits, logic, memory, and/orsoftware that receive instructions, issue instructions, controloperation, enable cleaning operations, enable endpoint measurements, andthe like. The integrated circuits include chips in the form of firmwarethat store program instructions, digital signal processors (DSPs), chipsdefined as Application Specific Integrated Circuit (ASICs), programmablelogic devices (PLDs), one or more microprocessors, or microcontrollersthat execute program instructions (e.g., software). The programinstructions are instructions communicated to the controller in the formof various individual settings (or program files), defining operationalparameters for carrying out a process on or for a semiconductor wafer.The operational parameters are, in some embodiments, a part of a recipedefined by process engineers to accomplish one or more processing stepsduring the fabrication of one or more layers, materials, metals, oxides,silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.

The controller, in some embodiments, is a part of or coupled to acomputer that is integrated with, coupled to the system, otherwisenetworked to the system, or a combination thereof. For example, thecontroller is in a “cloud” or all or a part of a fab host computersystem, which allows for remote access for wafer processing. Thecontroller enables remote access to the system to monitor currentprogress of fabrication operations, examines a history of pastfabrication operations, examines trends or performance metrics from aplurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process.

In some embodiments, a remote computer (e.g. a server) provides processrecipes to the system over a computer network, which includes a localnetwork or the Internet. The remote computer includes a user interfacethat enables entry or programming of parameters and/or settings, whichare then communicated to the system from the remote computer. In someexamples, the controller receives instructions in the form of settingsfor processing a wafer. It should be understood that the settings arespecific to a type of process to be performed on a wafer and a type oftool that the controller interfaces with or controls. Thus as describedabove, the controller is distributed, such as by including one or morediscrete controllers that are networked together and working towards acommon purpose, such as the fulfilling processes described herein. Anexample of a distributed controller for such purposes includes one ormore integrated circuits on a chamber in communication with one or moreintegrated circuits located remotely (such as at a platform level or aspart of a remote computer) that combine to control a process in achamber.

Without limitation, in various embodiments, the system includes a plasmaetch chamber, a deposition chamber, a spin-rinse chamber, a metalplating chamber, a clean chamber, a bevel edge etch chamber, a physicalvapor deposition (PVD) chamber, a chemical vapor deposition (CVD)chamber, an atomic layer deposition (ALD) chamber, an atomic layer etch(ALE) chamber, an ion implantation chamber, a track chamber, and anyother semiconductor processing chamber that is associated or used infabrication and/or manufacturing of semiconductor wafers.

It is further noted that although the above-described operations aredescribed with reference to a parallel plate plasma chamber, e.g., acapacitively coupled plasma chamber, etc., in some embodiments, theabove-described operations apply to other types of plasma chambers,e.g., a plasma chamber including an inductively coupled plasma (ICP)reactor, a transformer coupled plasma (TCP) reactor, conductor tools,dielectric tools, a plasma chamber including an electron cyclotronresonance (ECR) reactor, etc. For example, one or more RF generators arecoupled to an inductor within the ICP plasma chamber. Examples of ashape of the inductor include a solenoid, a dome-shaped coil, aflat-shaped coil, etc.

As noted above, depending on a process operation to be performed by thetool, the controller communicates with one or more of other toolcircuits or modules, other tool components, cluster tools, other toolinterfaces, adjacent tools, neighboring tools, tools located throughouta factory, a main computer, another controller, or tools used inmaterial transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

With the above embodiments in mind, it should be understood that some ofthe embodiments employ various computer-implemented operations involvingdata stored in computer systems. These computer-implemented operationsare those that manipulate physical quantities.

Some of the embodiments also relate to a hardware unit or an apparatusfor performing these operations. The apparatus is specially constructedfor a special purpose computer. When defined as a special purposecomputer, the computer performs other processing, program execution orroutines that are not part of the special purpose, while still beingcapable of operating for the special purpose.

In some embodiments, the operations, described herein, are performed bya computer selectively activated, or are configured by one or morecomputer programs stored in a computer memory, or are obtained over acomputer network. When data is obtained over the computer network, thedata may be processed by other computers on the computer network, e.g.,a cloud of computing resources.

One or more embodiments, described herein, can also be fabricated ascomputer-readable code on a non-transitory computer-readable medium. Thenon-transitory computer-readable medium is any data storage hardwareunit, e.g., a memory device, etc., that stores data, which is thereafterread by a computer system. Examples of the non-transitorycomputer-readable medium include hard drives, network attached storage(NAS), ROM, RAM, compact disc-ROMs (CD-ROMs), CD-recordables (CD-Rs),CD-rewritables (CD-RWs), magnetic tapes and other optical andnon-optical data storage hardware units. In some embodiments, thenon-transitory computer-readable medium includes a computer-readabletangible medium distributed over a network-coupled computer system sothat the computer-readable code is stored and executed in a distributedfashion.

Although some method operations, described above, were presented in aspecific order, it should be understood that in various embodiments,other housekeeping operations are performed in between the methodoperations, or the method operations are adjusted so that they occur atslightly different times, or are distributed in a system which allowsthe occurrence of the method operations at various intervals, or areperformed in a different order than that described above.

It should further be noted that in an embodiment, one or more featuresfrom any embodiment described above are combined with one or morefeatures of any other embodiment without departing from a scopedescribed in various embodiments described in the present disclosure.

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, it will be apparent thatcertain changes and modifications can be practiced within the scope ofappended claims. Accordingly, the present embodiments are to beconsidered as illustrative and not restrictive, and the embodiments arenot to be limited to the details given herein, but may be modifiedwithin the scope and equivalents of the appended claims.

The invention claimed is:
 1. A system for controlling directionality ofion flux at an edge region within a plasma chamber, comprising: a firstradio frequency (RF) generator that is configured to generate a first RFsignal; a first impedance matching circuit coupled to the first RFgenerator for receiving the first RF signal to generate a first modifiedRF signal; and a plasma chamber including: an edge ring; and a couplingring located below the edge ring and coupled to the first impedancematching circuit to receive the first modified RF signal, wherein thecoupling ring includes an electrode configured to generate a capacitancebetween the electrode and the edge ring to control the directionality ofthe ion flux upon receiving the first modified RF signal.
 2. The systemof claim 1, further comprising: a second RF generator configured togenerate a second RF signal; a second impedance matching circuit coupledto the second RF generator and configured to receive the second RFsignal to generate a second modified RF signal; and a chuck coupled tothe second impedance matching circuit and configured to receive thesecond modified RF signal to change an impedance of plasma within theplasma chamber, wherein the chuck is located besides the edge ring andthe coupling ring.
 3. The system of claim 1, wherein the electrode isembedded within the coupling ring, and is a wire mesh or a ring.
 4. Thesystem of claim 1, further comprising: a first insulator ring locatedbelow the coupling ring; a second insulator ring located below the firstinsulator ring; a cable extending through the second insulator ring, thefirst insulator ring, and a portion of the coupling ring to couple tothe electrode, wherein a portion of the coupling ring between theelectrode and the edge ring acts as a dielectric between the electrodeand the edge ring.
 5. The system of claim 4, further comprising a groundring located besides the first insulator ring.
 6. The system of claim 1,further comprising: a coax cable of a power pin coupled to theelectrode; a feed ring coupled at a point to the coax cable; and an RFrod coupled to the feed ring and the first impedance matching circuit.7. The system of claim 1, further comprising: a probe located within theplasma chamber; a sensor coupled to the probe and configured to measurea variable associated with ion flux; a host computer system coupled tothe sensor to determine based on the variable whether an amount of powersupplied by the first RF generator to the electrode is to be modified,wherein the host computer system is coupled to the first RF generator tochange the amount of power supplied by the first RF generator to theelectrode via the first impedance matching circuit.
 8. A system forcontrolling directionality of ion flux at an edge region within a plasmachamber, comprising: a first radio frequency (RF) filter that isconfigured to output a first filtered RF signal; a second RF filtercoupled to the first RF filter for receiving the first filtered RFsignal to output a second filtered RF signal; and a plasma chamberincluding: an edge ring; and a coupling ring located below the edge ringand coupled to the second RF filter, wherein the coupling ring includesan electrode configured to receive the second filtered RF signal tofurther generate a capacitance between the electrode and the edge ringto control the directionality of the ion flux upon receiving the secondfiltered RF signal.
 9. The system of claim 8, further comprising: an RFgenerator configured to generate an RF signal; an impedance matchingcircuit coupled to the RF generator and configured to receive the RFsignal to generate a modified RF signal; and a chuck coupled to theimpedance matching circuit and configured to receive the modified RFsignal to change an impedance of plasma within the plasma chamber,wherein the chuck is located besides the edge ring and the couplingring.
 10. The system of claim 8, wherein the electrode is embeddedwithin the coupling ring and is a wire mesh or a ring.
 11. The system ofclaim 8, further comprising: a first insulator ring located below thecoupling ring; a second insulator ring having a portion located belowthe first insulator ring; a power pin extending through the secondinsulator ring, the first insulator ring, and a portion of the couplingring to couple to the electrode, wherein a portion of the coupling ringbetween the electrode and the edge ring acts as a dielectric between theelectrode and the edge ring.
 12. The system of claim 11, furthercomprising a ground ring located besides the first insulator ring. 13.The system of claim 8, further comprising: a coax cable of a power pincoupled to the electrode; a feed ring coupled at a point to the coaxcable; and an RF rod coupled to the second RF filter that is coupled tothe feed ring.
 14. The system of claim 8, further comprising: a probelocated within the plasma chamber; a sensor coupled to the probe andconfigured to measure a variable associated with ion flux; a hostcomputer system coupled to the sensor to determine based on the variablewhether a capacitance of the first RF filter is to be modified; a motorcoupled to the host computer system; wherein the host computer system isconfigured to modify the capacitance of the first RF filter via themotor.
 15. A system for controlling directionality of ion flux at anedge region within a plasma chamber, comprising: a radio frequency (RF)filter that is configured to output a filtered RF signal; a plasmachamber including: an edge ring; and a coupling ring located below theedge ring and coupled to the RF filter to receive the filtered RFsignal, wherein the coupling ring includes an electrode configured togenerate a capacitance between the electrode and the edge ring tocontrol the directionality of the ion flux upon receiving the filteredRF signal.
 16. The system of claim 15, further comprising: an RFgenerator configured to generate an RF signal; an impedance matchingcircuit coupled to the RF generator and configured to receive the RFsignal to generate a modified RF signal; and a chuck coupled to theimpedance matching circuit and configured to receive the modified RFsignal to change an impedance of plasma within the plasma chamber,wherein the chuck is located besides the edge ring and the couplingring.
 17. The system of claim 15, wherein the electrode is embeddedwithin the coupling ring and is a wire mesh or a ring.
 18. The system ofclaim 15, further comprising: a first insulator ring located below thecoupling ring; a second insulator ring having a portion located belowthe first insulator ring; a power pin extending through the secondinsulator ring, the first insulator ring, and a portion of the couplingring to couple to the electrode, wherein a portion of the coupling ringbetween the electrode and the edge ring acts as a dielectric between theelectrode and the edge ring.
 19. The system of claim 18, furthercomprising a ground ring located besides the first insulator ring. 20.The system of claim 15, further comprising: a coax cable of a power pincoupled to the electrode; and a feed ring coupled at a point to the coaxcable.
 21. The system of claim 15, further comprising: a probe locatedwithin the plasma chamber; a sensor coupled to the probe and configuredto measure a variable associated with ion flux; a host computer systemcoupled to the sensor to determine based on the variable whether acapacitance of the RF filter is to be modified; a motor coupled to thehost computer system; wherein the host computer system is configured tomodify the capacitance of the RF filter via the motor.